Carpal tunnel syndrome is a disease within a larger group of musculoskeletal system disorders known as repetitive strain disorders or cumulative trauma disorders. These disorders arise from injuries caused by the buildup of daily damage from repetitive motions and impacts. The injuries can lead to problems in the fingers, hands, wrists, and forearms. These problems include numbness, burning or tingling sensations, pain, restricted movement, stiffness, muscle atrophy, weakness, and clumsiness. In more advanced cases, the symptoms can also manifest themselves in the upper arms, shoulders, and neck.
The repetitive motions or impacts that cause carpal tunnel syndrome can occur during such common activities as typing, operating pneumatic devices (e.g., jack-hammers and nail guns), knitting, and playing musical instruments.
Each individual movement or impact may cause damage that is naturally repaired by the mechanisms of healthy tissue. When the motions or impacts occur repeatedly, the damage compounds making it more difficult for the body to repair itself. Over time a restricted blood supply to these areas causes repetitive strain disorders, such as tendinitis and carpal tunnel syndrome. Tendinitis is an inflammation of the tendons, whereas carpal tunnel syndrome occurs when the median nerve is pinched or irritated in the carpal tunnel in the wrist.
The wrist has an arched structure of bones that combine with the transverse carpal ligament to define an opening through the wrist known as the carpal tunnel. The median nerve, which controls the first three to four fingers, and the flexor tendons, which attach to the bones in the fingers, all extend through the carpal tunnel into the hand.
Repetitively worked, flexor tendons eventually will become irritated. This irritation can cause an inflammation of the flexor tendons. Consequently, the flexor tendons will swell and thicken from overuse. The bones and ligament forming the carpal tunnel are not able to either adequately stretch or expand to accommodate the swollen and thickened flexor tendons. Thus, the inflammation or swelling of the flexor tendons squeezes the median nerve against the transverse carpal ligament, thereby exerting pressure on the median nerve. When the pressure becomes great enough, the median nerve cannot function normally and the above-noted problems and symptoms occur.
Other events can lead to increased pressure on the median nerve. The pressure can be caused by the swelling of the median nerve itself, arthritis, or mechanical pressures (i.e., outside stresses, such as vibration or pressure, or the force of fractured wrist bones). In each scenario, the increased pressure on the median nerve can cause the pinching, irritation, and inflammation that leads to carpal tunnel syndrome.
The problems that accompany carpal tunnel syndrome can be debilitating to sufferers. Often individuals with the syndrome awake from their sleep due to sharp pains shooting up their arms. Sufferers also find it increasingly difficult to perform simple tasks involving manual dexterity, such as grasping objects, writing, typing, opening jars, buttoning clothes, and tying shoelaces. This results in the inability of of sufferers to function not only in the home but also in the workplace.
There are many known devices and methods available for preventing and treating carpal tunnel syndrome.
One effective means of treatment is to avoid the activity that produced the carpal tunnel syndrome. However, this treatment is often impractical or impossible for most people, such as where the activity or activities are directly related to their livelihoods.
Anti-inflammatory medicines, certain vitamins, and cortisone injections have been used with varying degrees of success to alleviate the symptoms of carpal tunnel syndrome.
Strict posture requirements and frequent breaks from repetitive movement tasks and repetitive impact tasks are also suggested for preventing repetitive strain disorders. However, many workers are unavoidably subjected for extended periods of time to the highly repetitive motions and impacts that cause these disorders.
Once the injury manifests itself and is otherwise not responsive to treatment, surgery is available to correct the problem. Corrective surgery, sometimes referred to as a carpal tunnel release, requires cutting the tendons surrounding the nerve to alleviate the pressure. This procedure is expensive and risks further damaging the median nerve.
Wrist braces have been used to both prevent and treat carpal tunnel syndrome. Such braces use rigid stays to secure the hand, wrist, and distal forearm at an angle that reduces the stress and pressure on the median nerve. However, the braces currently on the market utilize stays that apply direct pressure to a portion of the hand overlying the carpal tunnel. Thus, the stays can actually add harmful pressure to the median nerve.
Thus, there is a need for a wrist brace that secures the hand, wrist and distal forearm but does not put any additional pressure on the carpal tunnel or median nerve.
U.S. Pat. No. 5,484,392 issued to Snyder et al. discloses a wrist support with a stay having an opening in its interior and flexible slits around its edges. The opening releases compression on the median nerve. The slits provide needed flexibility at the outer portions of the brace to improve movement. However, the stay of Snyder et al., must be wide enough to allow for both an interior opening wide enough to avoid contacting the carpal tunnel and lateral sides wide enough to adequately support the hand and wrist. Accordingly, the size of the brace of Synder et al., may prove to be cumbersome and make it difficult to perform certain activities making such a brace an impractical choice for many users suffering from carpal tunnel syndrome. Further, the stay of Snyder et al. is somewhat complex in design, adding to the cost of manufacture.